JPS5823925B2 - Heat radiation prevention device for furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat radiation preventive device that reduces heat radiation from a process tube or the like in a heat diffusion furnace or the like.

2. Description of the Related Art In the manufacturing process of semiconductor devices and the like, there are many heat treatment steps such as a step of thermally diffusing various impurities into semiconductor wafers.

In this heat treatment, a process tube generally made of quartz or the like is inserted into a large electric furnace, and the workpiece is placed inside the process tube and heated.

In such a heat treatment process, it is important to effectively prevent heat dissipation from the furnace to the outside in order to increase the thermal efficiency of the furnace and avoid placing an excessive burden on the furnace.

Generally, heat dissipation from an electric furnace is greatest particularly in the gap between the end face of the electric furnace and the process tube and the exposed part.

Conventionally, in order to prevent such heat dissipation, the gap between the process tube and the electric furnace was filled with a heat-resistant insulating material such as glass wool, or a collar-shaped heat reflector was fitted to the process tube to prevent air flow in the gap. Measures have been taken to block the

-However, recently, as the area of workpieces such as semiconductor wafers has become larger, process tubes with larger diameters have been used, and heat dissipation at both ends of the process tube has increased significantly. However, it is necessary to increase the heat output of the electric furnace, which places an excessive burden on the electric furnace, shortening the life of the electric furnace, making the temperature characteristics of the electric furnace unstable, and increasing power consumption. Problems could not be avoided.

An object of the present invention is to provide a heat radiation preventive device having a novel configuration that can eliminate the defects of the conventional heat radiation preventive device as described above and more effectively prevent heat radiation from a furnace.

The heat radiation preventive device of the present invention is composed of a relatively soft heat-resistant heat insulating material layer and a metal reinforcing plate that surrounds the heat insulating material layer, and the heat radiation preventive device is made of a relatively soft heat-resistant heat insulating material layer and a metal reinforcing plate surrounding the heat insulating material layer, and the heat radiation prevention device is made of a metal reinforcing plate that surrounds the heat insulating material layer. It is characterized by being formed so as to surround the adjacent parts without any gaps and to seal the gap between the end face part of the furnace and the process tube.

The present invention will be explained in more detail below with reference to Examples.

FIG. 1 is a longitudinal sectional view of a heat radiation preventive device showing one embodiment of the present invention.

That is, the heat radiation preventive device consisting of the heat-resistant heat insulating material layer 1 and its reinforcing plate 2 is formed in a cylindrical shape so as to surround the process tube 3 without any gap, and the part that contacts the furnace 4 is formed between the process tube 3 and the furnace. It is formed into a flange shape so as to seal the gap with 4.

This heat dissipation preventive tool is formed so as to be fitted into the process tube without any gaps, and a screw hole 5 is provided in the flange-like part of the heat dissipation preventive tool, and a nut 6 is provided in the end surface of the furnace.
Fix it by stopping it.

In this way, the gap between the process tube 3 and the furnace 4 can be completely sealed.

Furthermore, if glass wool 7 or the like is packed between the process tube 3 and the furnace 4 before installing the heat radiation prevention device, heat radiation can be more effectively prevented.

Here, as the heat-resistant heat insulating material 1, it is preferable to use a relatively soft and easily moldable material such as asbestos.

Further, as the reinforcing plate 2, it is preferable to use a material with relatively low thermal conductivity and durability, such as a stainless steel plate.

Figure 2 shows another embodiment of the present invention, and when the end of the process tube 3 is narrowed as in the example shown in this figure, heat dissipation in the axial direction of the process tube is prevented. Therefore, the effects of implementing the present invention will be even greater.

According to the implementation of the present invention as described above, in an electric furnace operated at about 1000°C, the required temperature of the heating element of the furnace can be lowered by 5 to 10°C compared to the conventional one, and the life of the electric furnace can be reduced by 5 to 10°C. This makes it possible to operate the furnace with high thermal efficiency.

Furthermore, since it is possible to effectively prevent temperature drops at both ends of the electric furnace, the temperature inside the furnace is stabilized, and at the same time, the temperature characteristics inside the furnace are improved, resulting in uniform product performance and improved reliability. It is also possible to obtain great effects.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are longitudinal cross-sectional views showing a heat radiation preventive device and its mounting manner according to an embodiment of the present invention, respectively. Explanation of symbols, 1...Heat-resistant insulation layer, 2...
... Reinforcement plate, 3... Process tube, 4.
...Furnace, 5...Screw hole, 6...
Screw, 7...Glass wool.

Claims (1)

[Claims] 1 Consisting of a relatively soft heat-resistant heat insulating layer and a metal reinforcing plate that surrounds the heat insulating layer, the process tube surrounds at least a part of the process tube protruding from the furnace close to the furnace without any gaps. A heat radiation prevention device for a furnace, which is formed to seal a gap between a furnace end face and a process tube, and is configured to be detachably attached to the process tube.